Smart cards or chip cards, as presently used, consist of a card of approximately the same size as a standard credit card that contain intelligence on the card itself. This intelligence is typically in the form of a memory circuit that can contain read only memory or read/write memory (random access memory) on the card. The information stored in the card's memory can then be used by the card reader or card interface device to detect certain information stored on the card, such as an instantaneous bank balance. The information stored in the card's memory can also be instantaneously updated, for example, the alteration of the security status of a specific badge holder. Cards of this type can also be used with cable television decoders or descramblers and with satellite systems.
Although the preferred embodiments of this invention are specifically directed to smart cards, it is equally applicable to connectors or similar devices. For example, this invention would be applicable to the use of connectors for smart keys and could even be used for memory cards of the type generally referred to as PCMCIA cards.
Among the problems that must be overcome for card connectors and card readers of this type to attain a satisfactory level of performance is that the connectors must function for a large number of card insertions, and the card connector must function in environments which can cause deterioration or damage to the contact interface of the data contacts and the end position switches. Typically the card connectors will be used in applications, such as in automatic teller machines or in security devices, in which a large number of cards will be used with a single card connector or reader. Over time the cards used in these applications can become deformed and can collect foreign substances that can interfere with the operation of the card reader. The cards can also become warped. The card connectors can also be used in environments, such as outdoor use in automatic teller machines, in which they are susceptible to environment contaminants, or in which oxides could build up over time. Since these applications employ relatively low electrical potential and current, the energy present in power applications to burn off these contaminants or oxides is not available. Therefore, it is desirable that a wiping contact between the data contacts and the card contact pads be established to ensure removal of contamination from the contact area. This wiping contact, however, must not be accompanied with excessive force that might damage the plating on the data contacts or the resilient data contacts themselves. A constant contact or wiping force is, therefore, desirable. This constant contact force can only be achieved by precisely positioning the data contacts relative to the smart card. Such precise positioning can be achieved by complicated and expensive card readers and/or by maintaining precise tolerances for the individual subcomponents and for the final assembly. Both of these options have added cost to prior art configurations.
U.S. Pat. No. 4,900,273, U.S. Pat. No. 5,103,255, and U.S. Pat. No. 5,334,034 disclose smart card readers or connectors. None of these smart connectors appear to employ means for reducing wear on data contacts in the connector or for preloading the data contacts. U.S. Pat. No. 5,380,997 discloses a card reader including a card holder and both reading wipers or contacts and other contacts biased into a plane further from the base than the reading wipers or contacts. U.S. Pat. No. 5,334,827 discloses a chip card reader in which the contact is in resilient abutment with an abutment surface on the housing and assumes a straight biased position.